1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor integrated circuit device having a SOI (silicon on insulator) structure in which electronic circuits are formed on a monocrystal semiconductor film laid on a dielectric member.
2. Description of the Related Art
Various methods of forming a monocrystallized semiconductor film having a SOI structure have been developed. However, formation of a monocrystallized film over a wide area is difficult in any of these methods. For example, when a polycrystalline silicon film formed on the entire surface of a dielectric member is recrystallized by using an energy beam such as a laser beam which irradiates the polycrystalline silicon film, a growth of the crystal grains proceeds from the periphery of the irradiated area to the center thereof, and a large number of nuclei thereof are formed and joined with each other, resulting in the inability to form a large monocrystal.
Several methods have been developed to form the islands of polycrystalline silicon on a SiO.sub.2 film which is a dielectric film formed on a monocrystal silicon substrate. The islands of the polycrystlline silicon are separated by a SiO.sub.2 layer for separation, as shown in FIG. 1. Each of the islands of the polycrystalline silicon has a dimension smaller than the diameter of a laser beam. Using the central portion of a Gaussian distributed laser beam and making the peripheral portion of each of the islands to be the heat absorbent layer, a monocrystal is grown by forming the different escape ways of the escape in absorbed heat in the heat absorbent layer.
In the method shown in FIG. 1, when the polycrystalline silicon layer has been monocrystallized, the islands of the monocrystal silicon separated by the SiO.sub.2 layer are obtained. This enables electronic circuits to be formed on the monocrystal silicon layer in a separate fashion. This method therefore allows excellent compatibility with the semiconductor integrated circuit device manufacturing process. However, the islands of the polycrystalline silicon must be formed smaller than the diameter of a laser beam, and the problem arises in that a monocrystal having a large area can not be formed.